@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');

:root {
    --primary: #1e3a5f;
    --primary-dark: #152a45;
    --primary-light: #2a4d7a;
    --secondary: #3b82f6;
    --accent: #f59e0b;
    --success: #22c55e;
    --error: #ef4444;
    --warning: #f59e0b;
    --bg: #f8fafc;
    --bg-secondary: #f1f5f9;
    --text: #1e293b;
    --text-secondary: #64748b;
    --border: #e2e8f0;
    --white: #ffffff;
    --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
    --radius: 8px;
    --radius-lg: 12px;
}
* { margin:0; padding:0; box-sizing:border-box; }
body { font-family:'Inter',-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif; background:var(--bg); color:var(--text); line-height:1.6; font-size:16px; }
h1,h2,h3,h4,h5,h6 { color:var(--primary); font-weight:600; line-height:1.3; }
h1 { font-size:2.5rem; margin-bottom:1rem; }
h2 { font-size:2rem; margin-bottom:.75rem; }
h3 { font-size:1.5rem; margin-bottom:.5rem; }
p { margin-bottom:1rem; }
a { color:var(--secondary); text-decoration:none; transition:color .2s; }
a:hover { color:var(--primary); }
.container { max-width:1200px; margin:0 auto; padding:0 20px; }
.content-shell { max-width:980px; margin:0 auto; }
.section { padding:60px 0; }
.section-sm { padding:28px 0; }
.card { background:var(--white); border-radius:var(--radius-lg); box-shadow:var(--shadow); padding:24px; margin-bottom:20px; }
.card.soft { background:var(--bg-secondary); box-shadow:none; border:1px solid var(--border); }
.btn { display:inline-flex; align-items:center; justify-content:center; padding:12px 24px; font-size:1rem; font-weight:500; border-radius:var(--radius); border:none; cursor:pointer; transition:all .2s; font-family:inherit; }
.btn-primary { background:var(--primary); color:var(--white); }
.btn-primary:hover { background:var(--primary-dark); color:var(--white); }
.btn-secondary { background:var(--bg-secondary); color:var(--text); border:1px solid var(--border); }
.btn-secondary:hover { background:var(--border); }
.btn-success { background:var(--success); color:var(--white); }
.btn-success:hover { background:#16a34a; color:var(--white); }
.btn-outline { background:transparent; color:var(--primary); border:1px solid var(--primary); }
.btn-outline:hover { background:rgba(30,58,95,0.08); }
.btn-lg { padding:14px 28px; font-size:1.05rem; }
.form-group { margin-bottom:20px; }
.form-label { display:block; font-weight:500; margin-bottom:8px; color:var(--text); }
.form-control { width:100%; padding:12px 16px; font-size:1rem; font-family:inherit; border:1px solid var(--border); border-radius:var(--radius); background:var(--white); color:var(--text); }
.form-control:focus { outline:none; border-color:var(--primary); box-shadow:0 0 0 3px rgba(30,58,95,0.1); }

.isbn-navbar { background:var(--primary); padding:16px 0; position:sticky; top:0; z-index:100; }
.isbn-navbar-container { display:flex; justify-content:space-between; align-items:center; max-width:1200px; margin:0 auto; padding:0 20px; gap:20px; }
.isbn-navbar-brand { color:var(--white)!important; font-size:1.5rem; font-weight:700; text-decoration:none; display:inline-flex; align-items:center; justify-content:flex-start; flex:0 0 auto; }
.isbn-navbar-brand span { color:var(--white)!important; }
.isbn-navbar-brand:hover, .isbn-navbar-brand:focus { color:var(--white)!important; text-decoration:none; }
.isbn-navbar-nav { display:flex; list-style:none; gap:8px; margin:0; padding:0; align-items:center; flex:0 0 auto; }
.isbn-navbar-nav li { display:inline-flex; }
.isbn-navbar-nav a { color:rgba(255,255,255,0.8); padding:8px 16px; border-radius:var(--radius); transition:all .2s; font-size:.95rem; font-weight:500; }
.isbn-navbar-nav a:hover, .isbn-navbar-nav a.active { color:var(--white); background:rgba(255,255,255,0.1); }
.isbn-navbar-toggle { display:none; background:none; border:none; cursor:pointer; padding:8px; flex-direction:column; gap:5px; }
.isbn-navbar-toggle span { display:block; width:22px; height:2px; background:rgba(255,255,255,0.8); border-radius:2px; transition:all .3s; }
.isbn-navbar-toggle:hover span { background:white; }

.hero { background:linear-gradient(135deg,var(--primary) 0%,var(--primary-light) 100%); color:var(--white); padding:80px 0; }
.hero h1,.hero h2,.hero h3,.hero p { color:var(--white); }
.hero .btn-secondary { background:rgba(255,255,255,0.12); color:#fff; border:1px solid rgba(255,255,255,0.25); }
.hero .btn-secondary:hover { background:rgba(255,255,255,0.2); color:#fff; }
.guide-hero { padding:72px 0 56px; }
.guide-section { padding:48px 0; }
.features-grid,.guide-grid { display:grid; grid-template-columns:repeat(auto-fit,minmax(240px,1fr)); gap:24px; }
.steps { display:grid; grid-template-columns:repeat(auto-fit,minmax(180px,1fr)); gap:24px; }
.step { background:var(--white); border-radius:var(--radius-lg); box-shadow:var(--shadow); padding:24px; text-align:center; }
.step-number { width:42px; height:42px; border-radius:999px; background:var(--primary); color:var(--white); display:flex; align-items:center; justify-content:center; font-weight:700; margin:0 auto 16px; }
.card-icon { font-size:2rem; margin-bottom:12px; }
.price-tag { font-size:2.5rem; font-weight:700; color:var(--primary); }
.price-tag span { font-size:1rem; font-weight:500; color:var(--text-secondary); }
.stat-number { font-size:1.8rem; font-weight:700; color:var(--primary); }
.stat-label,.text-muted,.page-intro { color:var(--text-secondary); }
.quantity-selector { display:flex; align-items:center; border:1px solid var(--border); border-radius:10px; overflow:hidden; }
.quantity-btn { border:0; background:var(--bg-secondary); padding:10px 14px; font-size:1.2rem; cursor:pointer; }
.quantity-input { width:72px; text-align:center; border:0; padding:10px; }
.cart-section { background:var(--white); border-radius:var(--radius-lg); box-shadow:var(--shadow); padding:24px; }
.cart-item,.cart-total { display:flex; justify-content:space-between; margin-bottom:10px; }
.cart-total { padding-top:12px; border-top:1px solid var(--border); font-weight:700; }
.cta-band { background:linear-gradient(135deg,var(--primary) 0%,var(--primary-light) 100%); color:#fff; border-radius:var(--radius-lg); padding:40px 28px; text-align:center; }
.cta-band h2,.cta-band p { color:#fff; }
.link-grid { display:grid; grid-template-columns:repeat(auto-fit,minmax(220px,1fr)); gap:14px; }
.link-grid a { display:block; padding:14px 16px; background:#fff; border:1px solid var(--border); border-radius:12px; color:var(--primary); font-weight:600; box-shadow:var(--shadow); }
.table-responsive { overflow-x:auto; }
.badge { display:inline-block; padding:4px 12px; font-size:.75rem; font-weight:500; border-radius:9999px; }
.badge-success { background:rgba(34,197,94,.1); color:var(--success); }
.text-center { text-align:center; }
.mb-0{margin-bottom:0}.mb-2{margin-bottom:16px}.mb-3{margin-bottom:24px}.mb-4{margin-bottom:32px}.mb-5{margin-bottom:40px}.mt-4{margin-top:32px}.mt-5{margin-top:40px}.w-100{width:100%}
.footer { background:var(--primary); color:var(--white); padding:40px 0; margin-top:60px; }
.footer a { color:rgba(255,255,255,0.82); }
.footer a:hover { color:var(--white); }
.footer-links { list-style:none; padding-left:0; }
.footer-links li { margin-bottom:8px; }
.footer-brand { font-size:1.2rem; font-weight:700; color:#fff; }
.legal-content ul,.legal-content ol { margin-bottom:1rem; padding-left:1.2rem; }

@media (max-width: 640px) {
    .isbn-navbar-toggle { display:flex; }
    .isbn-navbar-nav { display:none; position:absolute; top:72px; left:0; right:0; background:var(--primary); flex-direction:column; align-items:stretch; padding:16px 20px 20px; box-shadow:var(--shadow-lg); }
    .isbn-navbar-nav.open { display:flex; }
    .isbn-navbar-nav li { display:flex; }
    .isbn-navbar-nav a { width:100%; }
    h1 { font-size:2rem; }
    h2 { font-size:1.6rem; }
    .hero { padding:56px 0; }
}